The smallest lowest cost launch vehicle (Pegasus) capable of putting a payload into orbit is based on air launch.

NASA studies conducted over twenty years ago concluded that air launch of the shuttle at 30,000 feet while traveling at 400 knots would not reduce the volume of the external tank but would reduce the size of the solid boosters by 50%, eliminating one million pounds of propellant and cutting burn time from two minutes to one minute. This same NASA study concluded a mothership aircraft capable of carrying the resulting three million pounds would itself weigh two million pounds (although a Boeing study done in the early seventies of a heavylift bulk cargo carrier aircraft concluded that an aircraft with an empty weigh of 800,000 to 900,000 lbs could carry a payload of 2.5 million pounds).

Ground launch forces a rocket to accelerate to supersonic speed in the densest part of the atmosphere. The shuttle, for example, hits Max Q (maximum pressure/aero drag) at only 30,000 feet when it attains Mach One.

Egads! It's the Return of Franklin! You are one determined dude. You're even reposting that link which (indirectly) got you kicked off last time.

So tell us Franky ... why didn't NASA go with an air-launched shuttle? I mean if it was so obviously a superior strategy to ground-launch.

A conspiracy right? Right?

DKH

(P.S. next time pick a name which isn't too obvious, I'm assuming that you're trying to rebuild credibility here right?)

Why didn't NASA go with an escape system? Or liquid propellant boosters? Or flyback boosters? Or all the other things they've studied which said would result in a safer more robust and resilient shuttle system?

Single IP is easy to get around unless you have a dedicated IP.. even I, for example, could get around it with shutting off my DSL modem for about 10 seconds.. but IP range is much more thorough. He'd have to get a whole new ISP, or at least do something like use his ISP's dial-up server (if he has broadband and they give him that perk, like mine does) to get around it.. at least from home, if that's where he's doing this from.

I ask not to try and give him or any other potential troublemaker ideas.. but to try and help you get rid of him. You guys seem to have quite a problem with returning trolls. (is this the same guy as Principles, or someone else?) If you can answer the above paragraph properly, you should be able to eliminate all but the most dedicated (read: psychotic) troublemakers.

_________________"Floating down the sound resounds around the icy waters underground.."

Single IP is easy to get around unless you have a dedicated IP.. even I, for example, could get around it with shutting off my DSL modem for about 10 seconds.. but IP range is much more thorough. He'd have to get a whole new ISP, or at least do something like use his ISP's dial-up server (if he has broadband and they give him that perk, like mine does) to get around it.. at least from home, if that's where he's doing this from.

I ask not to try and give him or any other potential troublemaker ideas.. but to try and help you get rid of him. You guys seem to have quite a problem with returning trolls. (is this the same guy as Principles, or someone else?) If you can answer the above paragraph properly, you should be able to eliminate all but the most dedicated (read: psychotic) troublemakers.

You might be able to get a range that blocks just the server he connects to, and not have to block the entire ISP. That would minimize the potential loss of users. I've also heard people mention blocking the MAC address off a NIC, for troublemakers using broadband.. but I don't know if it's even possible.

_________________"Floating down the sound resounds around the icy waters underground.."

Either way the problem is not so great. Franklinstein is just not very imaginative so he's fairly easy to spot ... and that flurry of recent trolls is just a natural consequence of all the attention coming from the Xprize being won and, predictably, didn't last very long.

I think this forum is just not popular enough for dedicated trolls (I don't count Franklin as a dedicated troll, he's more of an accidental troll) to bother with ... not enough rocket-heads around her to make bothering them with worth the bother.

Eh ... it's a hypothesis. Not enough data for a theory, but it's all I've got.

Yesterday I got the new edition of Wirtschaftswoche ( emebrs of the bdvb get it on Saturday while others get it on Monday.

There is an article in this new edition reporitng that Ohio Airships has developed a Zeppeline landing like an usual airplane but consuming a fraction of the energy only.

This hybrid called Dynalifter will do its maiden flight in May this year.

It's heavier than air and so has very little problems with ground winds up to 30 nodes.

It's meant for heavy cargo and the largest version is 300 meters long and can carry up to 200 tons.

What about using such a vehicle for air launch? I am not talking about concepts already existing here - I am not thinking of JP Aeropsace, ILAT or The da Vinci Project. My question is if a White Knight including such a zeppeline might be able to carry up to twice the weight of a fueld CXV-booster-propellant-combination.

In betwwen I recognized that I have to correct myself a bit - I was thinking about the Very Large Aircraft to launch the CXV but not of WK or WK2.

Hello, culture,

I had in mind a Very Large Aircraft with the modification to include the zeppeline which has been reported about. It would be interesting to know if such a VLA could carry significantly more than the already designed VLA to the launch-altitude.

If it is possible then this would be interesting since the VLA as it is would launch a CXV weighing 3.6 tons and six persons. If a VLA including the zeppeline could launch around 7 tons then 10 to 12 persons could be aboard, cargo could be included instead and so on.

The question simply is if the payload- or launch-capacity of the VLA could be significantly increased that way.

I had in mind a Very Large Aircraft with the modification to include the zeppeline which has been reported about. It would be interesting to know if such a VLA could carry significantly more than the already designed VLA to the launch-altitude. (...)

The question simply is if the payload- or launch-capacity of the VLA could be significantly increased that way.

Not very likely to be used, Mister.

Any type of airship - Zeppelin, Dynalifter, Skycat, Cargolifter or any other - necessarily has a very significant volume displacement. That's because it needs buoyancy. By consequence, the front area and thereby the atmospheric drag at higher speed is also big. That means that any vehicle with significant buoyancy would be OK for lifting large payloads and gently carrying them around, but not for fast travel, and not at a very high altitude (this is because air pressure is lower at altitude). But for an air-launch vehicle, the efficiency of your carrier aircraft is exactly best if it flies high and fast. That's not the specialty of airships.

Yes, there are high-altitude balloons and also plans for high-altitude airships, but they are slow, and the payload fraction becomes surprisingly small, so the advantages of lighter-than-air diminish. If anything, a monster Antonov or Superduperjumbo would be a likelier bet.

BTW, there's also a law-of-diminishing-return for very large aircraft, but the technologies to get around that seem to me to offer more scope.

Regards
Max

_________________There's space for all of us, if each will leave some space for the next one

The ideas expressed above are my own, not necessarily those of my employer.